Optimization of a Dynamic Model of Magnetic Actuation of an Origami Mechanism

2015 ◽  
Author(s):  
Landen Bowen ◽  
Kara Springsteen ◽  
Mary Frecker ◽  
Timothy Simpson
Keyword(s):  
Dynamic Models ◽  
Active Material ◽  
Joint Stiffness ◽  
Design Tool ◽  
Magnetic Actuation ◽  
Cost Weight ◽  
Shape Morphing ◽  
Self Assembling ◽  
Optimization Routine ◽  
Potential Use

Self-folding origami has the potential to be utilized in novel areas such as self-assembling robotics and shape-morphing structures. Important decisions in the development of such applications include the choice of active material and its placement on the origami model. With proper placement, the error between the actual and target shapes can be minimized along with cost, weight, and power requirements. Through the incorporation of dynamic models of self-folding origami mechanisms into an optimization routine, optimal orientations for magnetically-active material are identified that minimize error to specified target shapes. The dynamic models, created using Adams 2014, are refined by improvements to magnetic material simulation and more accurate joint stiffness characterization. Self-folding dynamic models of the waterbomb base and Shafer’s Frog Tongue are optimized, demonstrating the potential use of this process as a design tool for other self-folding origami mechanisms.

Trade Space Exploration of Magnetically Actuated Origami Mechanisms

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Landen Bowen ◽  
Kara Springsteen ◽  
Mary Frecker ◽  
Timothy Simpson
Keyword(s):  
Magnetic Material ◽  
Dynamic Models ◽  
Active Material ◽  
Approximation Error ◽  
Joint Stiffness ◽  
Design Tool ◽  
Target Shape ◽  
Self Assembling ◽  
Magnetically Actuated ◽  
Trade Space Exploration

Self-folding origami has the potential to be utilized in novel areas such as self-assembling robots and shape-morphing structures. Important decisions in the development of such applications include the choice of active material and its placement on the origami model. With proper active material placement, the error between the actual and target shapes can be minimized along with cost, weight, and input energy requirements. A method for creating magnetically actuated dynamic models and experimentally verifying their results is briefly reviewed, after which the joint stiffness and magnetic material approximations used in the dynamic model are discussed in more detail. Through the incorporation of dynamic models of magnetically actuated origami mechanisms into the Applied Research Laboratory's trade space visualizer (atsv), the trade spaces of self-folding dynamic models of the waterbomb base and Shafer's frog tongue are explored. Finally, a design tradeoff is investigated between target shape approximation error and the placement of magnetic material needed to reach a target shape. These two examples demonstrate the potential use of this process as a design tool for other self-folding origami mechanisms.

scholarly journals Exploring the Effect of the Irradiation Time on Photosensitized Dendrimer-Based Nanoaggregates for Potential Applications in Light-Driven Water Photoreduction

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1316 ◽  
Author(s):  
Martínez ◽  
Inostroza-Rivera ◽  
Durán ◽  
Molero ◽  
Bonardd ◽  
...  
Keyword(s):  
Active Sites ◽  
Methyl Viologen ◽  
Irradiation Time ◽  
Pt Nanoparticles ◽  
Morphological Properties ◽  
Fourth Generation ◽  
Self Assembling ◽  
Potential Applications ◽  
Potential Use

Fourth generation polyamidoamine dendrimer (PAMAM, G4) modified with fluorescein units (F) at the periphery and Pt nanoparticles stabilized by L-ascorbate were prepared. These dendrimers modified with hydrophobic fluorescein were used to achieve self-assembling structures, giving rise to the formation of nanoaggregates in water. The photoactive fluorescein units were mainly used as photosensitizer units in the process of the catalytic photoreduction of water propitiated by light. Complementarily, Pt-ascorbate nanoparticles acted as the active sites to generate H2. Importantly, the study of the functional, optical, surface potential and morphological properties of the photosensitized dendrimer aggregates at different irradiation times allowed for insights to be gained into the behavior of these systems. Thus, the resultant photosensitized PAMAM-fluorescein (G4-F) nanoaggregates (NG) were conveniently applied to light-driven water photoreduction along with sodium L-ascorbate and methyl viologen as the sacrificial reagent and electron relay agent, respectively. Notably, these aggregates exhibited appropriate stability and catalytic activity over time for hydrogen production. Additionally, in order to propose a potential use of these types of systems, the in situ generated H2 was able to reduce a certain amount of methylene blue (MB). Finally, theoretical electronic analyses provided insights into the possible excited states of the fluorescein molecules that could intervene in the global mechanism of H2 generation.

A Simplified Model of Desiccant Wheel and Implementation in a Design Tool

2008 ◽  
Author(s):  
Fatemeh Esfandiari Nia ◽  
Dolf van Paassen
Keyword(s):  
Design Tool ◽  
Weather Data ◽  
Physical Parameters ◽  
Transfer Model ◽  
Desiccant Wheel ◽  
New Class ◽  
Sensitivity Studies ◽  
Optimization Routine ◽  
The Given ◽  
Air Streams

A new class of heat and mass transfer model for a desiccant wheel has been presented and implemented in a design tool. Having studied the behavior of the system in different conditions and sensitivity studies, two physical parameters have been chosen to make simplified models or correlations. Using 1500 data of model solutions, two correlations have been made by an optimization routine in Matlab. These equations correlate outlet air conditions of a desiccant wheel to inlet air conditions of air streams and also the wheel and air speeds. The correlations are limited to be used only in the given range of air conditions and wheel speed. However, the range covers the practical situation that usually happens according to the weather data. The behavior of air conditions in Mollier diagram shows that the error for simulation of a typical cooling cycle to calculate supply air conditions is reduced with a factor of almost 3 times smaller. This shows that even in those ranges with low accuracy the correlations are useful. These simplified equations will be used in the design tools as has been presented in details in this paper.

Atom Transfer Radical Polymerization Functionalization on Polypropylene Films for Immobilizing Active Compounds

2018 ◽  
Vol 71 (7) ◽  
pp. 534 ◽  
Author(s):  
Cintia B. Contreras ◽  
Ricardo Toselli ◽  
Miriam C. Strumia
Keyword(s):  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Covalent Binding ◽  
Active Material ◽  
Antimicrobial Properties ◽  
Atom Transfer ◽  
Polypropylene Films ◽  
Epoxy Groups ◽  
Potential Use ◽  
Surface Chemical Modification

This work proposes the surface chemical modification of polypropylene films (PP) by atom transfer radical polymerization (ATRP) using glycidyl methacrylate (GMA) as the graft monomer. At a later stage, the epoxy groups of PP-g-PGMA were used for covalent binding of glucose oxidase (GOD) to obtain an active material (PP-g-PGMA-GOD) with 9.38 ± 0.06 mg cm−2 of enzyme bonded on the surface of PP. Preliminary microbiological studies have shown that this methodology of covalent binding of the enzyme onto the PP surface allowed its activity to be maintained. Therefore, this advantage would give to PP-g-PGMA-GOD films a potential use as an active packaging material if further specific studies on their antimicrobial properties can be verified.

Comparing model-based control methods for simultaneous stiffness and position control of inflatable soft robots

2020 ◽  
pp. 027836492091196
Author(s):  
Charles M. Best ◽  
Levi Rupert ◽  
Marc D. Killpack
Keyword(s):  
Dynamic Models ◽  
Position Control ◽  
Sliding Mode ◽  
Joint Stiffness ◽  
Variable Stiffness ◽  
Soft Robots ◽  
End Effector ◽  
Simultaneous Control ◽  
Stiffness Model ◽  
Stiffness Control

Inflatable robots are naturally lightweight and compliant, which may make them well suited for operating in unstructured environments or in close proximity to people. The inflatable joints used in this article consist of a strong fabric exterior that constrains two opposing compliant air bladders that generate torque (unlike McKibben actuators where pressure changes cause translation). This antagonistic structure allows the simultaneous control of position and stiffness. However, dynamic models of soft robots that allow variable stiffness control have not been well developed. In this work, a model that includes stiffness as a state variable is developed and validated. Using the stiffness model, a sliding mode controller and model predictive controller are developed to control stiffness and position simultaneously. For sliding mode control (SMC), the joint stiffness was controlled to within 0.07 Nm/rad of a 45 Nm/rad command. For model predictive control (MPC) the joint stiffness was controlled to within 0.045 Nm/rad of the same stiffness command. Both SMC and MPC were able to control to within 0.5° of a desired position at steady state. Stiffness control was extended to a multiple-degree-of-freedom soft robot using MPC. Controlling stiffness of a 4-DOF arm reduced the end-effector deflection by approximately 50% (from 17.9 to 12.2cm) with a 4 lb (1.8 kg) step input applied at the end effector when higher joint stiffness (40 Nm/rad) was used compared with low stiffness (30 Nm/rad). This work shows that the derived stiffness model can enable effective position and stiffness control.

Modeling and control of biologically inspired flying robots

Robotica ◽  
2011 ◽  
Vol 30 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Micael S. Couceiro ◽  
J. Miguel A. Luz ◽  
Carlos M. Figueiredo ◽  
N. M. Fonseca Ferreira
Keyword(s):  
Dynamic Models ◽  
Dynamic Control ◽  
Biologically Inspired ◽  
Modeling And Control ◽  
High Level ◽  
New Generation ◽  
And Control ◽  
Level Calculation ◽  
Potential Use ◽  
Flying Robots

SUMMARYThis paper covers a wide knowledge of physical and dynamical models useful for building flying robots and a new generation of flying platform developed in the similarity of flying animals. The goal of this work is to develop a simulation environment and dynamic control using the high-level calculation tool MatLab and the modeling, simulation, and analysis of dynamic systems tool Simulink. Once created the dynamic models to study, this work involves the study and understanding of the dynamic stability criteria to be adopted and their potential use in the control of flying models.

scholarly journals Self-assembling ultrashort NSAID-peptide nanosponges: multifunctional antimicrobial and anti-inflammatory materials

RSC Advances ◽  
2016 ◽  
Vol 6 (115) ◽  
pp. 114738-114749 ◽  
Author(s):  
A. P. McCloskey ◽  
S. M. Gilmore ◽  
J. Zhou ◽  
E. R. Draper ◽  
S. Porter ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Multifunctional Materials ◽  
Design Synthesis ◽  
Self Assembling ◽  
Anti Inflammatory ◽  
Potential Use

This paper outlines the design, synthesis and characterisation of innovative NSAID-peptide gelators which demonstrate antimicrobial and anti-inflammatory properties and have potential use as multifunctional materials for biomedical applications.

Fabrication and Performance of Magneto-Active Elastomer Composite Structures

2014 ◽  
Author(s):  
Paris von Lockette
Keyword(s):  
Rare Earth ◽  
Composite Structures ◽  
Active Material ◽  
Cross Product ◽  
Magnetic Actuation ◽  
Active Structures ◽  
And Performance ◽  
Origami Engineering ◽  
Printing Techniques ◽  
Initial Results

This works discusses the use of magneto-active elastomer (MAE) as an active material for use in origami engineering and other applications where transformation of a composite structure between target shapes is desired. Magneto-active elastomer, as the name implies, consists of magnetic powders dispersed in an elastomer (polymer) fluid which is subsequently cured in the presence of a magnetic field to produce a net remanent magnetization in the cured solid. Having their own internal magnetization, MAE materials are affected by both magnetic forces, due to gradients in local field, as well as magnetic torques resulting from the cross product of the field and the magnetization. In this fashion, patches of MAE material, distributed throughout a non-magnetic elastomeric structure, act as distributed actuators producing deformed shapes. The use of rare-Earth magnets as the magnetic actuation elements is also investigated. The work highlights experimental efforts to develop structures with integrated MAE patches and rare-Earth magnets of varying magnetization orientations using multi-step casting processes and 3D printing techniques. Initial results show success at generating active structures having locally oriented MAE patches and magnets in accordion, water bomb and and Miru fold patterns.

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